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Diffstat (limited to 'rotord/src/mtrand.cpp')
| -rw-r--r-- | rotord/src/mtrand.cpp | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/rotord/src/mtrand.cpp b/rotord/src/mtrand.cpp new file mode 100644 index 0000000..c0a4e48 --- /dev/null +++ b/rotord/src/mtrand.cpp @@ -0,0 +1,50 @@ +// mtrand.cpp, see include file mtrand.h for information + +#include "mtrand.h" +// non-inline function definitions and static member definitions cannot +// reside in header file because of the risk of multiple declarations + +// initialization of static private members +unsigned long MTRand_int32::state[n] = {0x0UL}; +int MTRand_int32::p = 0; +bool MTRand_int32::init = false; + +void MTRand_int32::gen_state() { // generate new state vector + for (int i = 0; i < (n - m); ++i) + state[i] = state[i + m] ^ twiddle(state[i], state[i + 1]); + for (int i = n - m; i < (n - 1); ++i) + state[i] = state[i + m - n] ^ twiddle(state[i], state[i + 1]); + state[n - 1] = state[m - 1] ^ twiddle(state[n - 1], state[0]); + p = 0; // reset position +} + +void MTRand_int32::seed(unsigned long s) { // init by 32 bit seed + state[0] = s & 0xFFFFFFFFUL; // for > 32 bit machines + for (int i = 1; i < n; ++i) { + state[i] = 1812433253UL * (state[i - 1] ^ (state[i - 1] >> 30)) + i; +// see Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier +// in the previous versions, MSBs of the seed affect only MSBs of the array state +// 2002/01/09 modified by Makoto Matsumoto + state[i] &= 0xFFFFFFFFUL; // for > 32 bit machines + } + p = n; // force gen_state() to be called for next random number +} + +void MTRand_int32::seed(const unsigned long* array, int size) { // init by array + seed(19650218UL); + int i = 1, j = 0; + for (int k = ((n > size) ? n : size); k; --k) { + state[i] = (state[i] ^ ((state[i - 1] ^ (state[i - 1] >> 30)) * 1664525UL)) + + array[j] + j; // non linear + state[i] &= 0xFFFFFFFFUL; // for > 32 bit machines + ++j; j %= size; + if ((++i) == n) { state[0] = state[n - 1]; i = 1; } + } + for (int k = n - 1; k; --k) { + state[i] = (state[i] ^ ((state[i - 1] ^ (state[i - 1] >> 30)) * 1566083941UL)) - i; + state[i] &= 0xFFFFFFFFUL; // for > 32 bit machines + if ((++i) == n) { state[0] = state[n - 1]; i = 1; } + } + state[0] = 0x80000000UL; // MSB is 1; assuring non-zero initial array + p = n; // force gen_state() to be called for next random number +}
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